Nividia or ATI, Intel or AMD

[WSP_Zoop]

Il-2 definitely runs better on Nividia than ATI using open GL.
I'm considering a new rig for CoD.
The best bang for the buck seems to be AMD and ATI.
However, on the last Vcard upgrade for IL-2 I bought ATI and had to change back to Nividia.
Is there a general consensus as to which brand of Vcard and CPU that works best with CoD.
I have not played CoD, I have it backordered at Ubishop and it has not been made available as yet.
Any help would be most appreciated.